The microstructure and magnetic properties i.e. the initial permeabili
ty, magnetic after-effect and coercivity for the as-quenched and annea
led at different temperatures Fe79.5Cu1Nb3Si13.5B9 samples are studied
After annealing the samples at 573 K for 1 h the decrease of the init
ial permeability and increase of the disaccommodation amplitude are ob
served These are connected with a local anisotropy induced during this
treatment. The increase of the annealing temperature causes the impro
vement of soft magnetic properties. However, after annealing the toroi
dal samples at 723 K for 1 h a magnetic hardening is observed It seems
to be connected with the appearance of alpha Fe-Si nuclei and cluster
s enriched in Cu. Moreover, it was stated that the cooling conditions
of the samples influence also their magnetic properties. Therefore, th
e values of coercivity obtained for annealed strips in comparison with
corresponding results of mu' obtained for toroids are shifted towards
higher temperature by 50 K.